Aircraft electrical power systems have power distribution panels (sometimes called “power panels”) configured to direct power from one or more power sources to one or more loads. Example power sources include generators from the engines of the aircraft, batteries, or auxiliary power units (APUs). Example loads include cabin lighting, hydraulic motors, cabin air compressors, or engine electric start motor controllers, to name a few.
Power distribution panels include high power contactors operable to selectively direct power between the power sources and the loads. The contactors are individual, replaceable units that mount to a printed wire board (PWB) via terminal posts or pads. The power distribution panel contains current-sensing features and control functions configured selectively to open or close the contactors. Power from the power sources is directed to the power distribution panel by way of feeder cables, which are electrically coupled to bus bars by way of an intermediate connector, known as a lug. The bus bars are electrically coupled to a contactor. When closed, the contactor is configured to direct power to one or more loads.
The components associated with the power distribution panel, including the feeder cables, bus bars, and the contactors, can generate significant heat during operation. Further, the different components may be rated to operate at different temperatures. The feeder cables typically are rated to operate at a higher temperature than the contactors. The contactors are cooled, in some examples, by exposure to ambient air.